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GacoFlex S20 Series

Solvent-Free Silicone Roof Coating System

Before you tear-off and replace a flat or low slope roof, call Gaco. The GacoFlex Solvent-Free Silicone Roofing System offers decades of proven performance and protection for renewing weathered or leaking roofs — large or small, flat or sloped.

Why Gaco Silicone Roof Coating Systems?

A worn-out or leaking roof doesn’t always have to be ripped off and replaced. Whether you’re a roofing contractor or building owner, there’s another solution to consider: silicone roof coatings. Silicone roof coatings were first used in the 1960s and have since greatly advanced to become an excellent roofing material and economical alternative to re-roofing. Silicone coatings are fast and easy to apply and deliver decades of protection. The GacoFlex Solvent-Free Silicone Roof Coating System can be applied to almost any existing roofing surface — large or small, flat or sloped — to shield it from damaging ultraviolet light, permanent ponding water, and severe weather.  


For new construction applications, or where a complete tear off is required, Gaco can offer a full roofing system. Starting from the deck with our polyisocyanurate spray foam insulation and capped with our S20 coating (similar to S42) providing a monolithic insulation and waterproofing system.

GacoFlex S20 Benefits

GacoFlex S20 is a leading silicone roof coating. Put the whole S20 Series Silicone Roof Coating System to work for you, not just the coating, to enjoy exceptional coverage and results for years to come. 


Building and business owners can expect benefits from using silicone, but also in working with Gaco. 


  • Seamless Process: Gaco is easy to work with and can take care of your business every step of the way. We make our products, install them, and warranty them. We’re a top-to-bottom partner that saves you from having to coordinate with contractors, suppliers, payments, and so on. 
  • Speedy Installation: Gaco silicone roof coating systems come with everything your contractor needs to work quickly and efficiently. You can count on a fast installation and quick resolution to your weathered roof problems. 
  • Durability: Permanence is a key advantage of using silicone. Silicone doesn’t degrade, chalk, or crack under brutal ultraviolet rays. 
  • Moisture Resistance: Silicone forms a smooth, seamless membrane that can withstand permanent ponding water without softening. As a material, it resists mold, mildew, and staining. Your GacoFlex S20 Series roof coating can be rained on within 2 hours of installation! 
  • Potential Energy Savings: A white silicone roof is a reflective roof, meaning it reflects 88% of UV rays (compared to 17% for a non-reflective roof), according to the EPA. Reflectivity translates to cost savings. According to the EPA, you can expect net annual savings of about 50 cents per square foot of reflective roof. GacoFlex maintains significantly higher whiteness and solar reflectivity over time when compared to other silicones. 
  • Best Warranty in the Business: We stand behind our products and offer Qualified Applicators a full-system labor and material warranty on GacoFlex S20 Series and S2100 Series Silicone Roof Coating Systems when applied according to Gaco specifications. 


And if you’re a contractor who’s applying a GacoFlex Silicone Coating? Expect: 


  • Simple Installation: Work with the full GacoFlex Solvent-Free Silicone Roof Coating System, and you’ll get all of the compatible products you need in the right amounts to get the job done quickly. Our systems include everything from pre-install roof cleaners to post-install tool cleaners. 
  • Solutions for Everything: Trying to solve for blisters or cracks in spray polyurethane foam? Need to cover an uneven surface? We’ve got your back. There’s a GacoFlex product for almost any difficult situation you might run into while renewing a roof.  
  • Supporting Partner: Consider us your roofing business’s biggest advocate. We’re committed to developing solutions that help you exceed your customers’ expectations and grow your business. 


Gaco S20 System Installation

The Gaco S20 system installation process involves five simple steps: 


  1. Make any necessary repairs and clean the roof surface. 
  2. Seal and/or prime the roof surface (as required). No primer is needed if you’re applying silicone to an existing silicone surface.
  3. Prepare seams and fasteners. Create or repair flashings. 
  4. Apply GacoFlex S20 Silicone Coating. 
  5. Install a rooftop walkway for pedestrian access. Granules can also be added to provide traction and wear resistance. (as required)


Once the installation is complete, don’t forget to clean off any tools or spray equipment used to apply GacoFlex Silicone Coatings. GacoFlex T5135 Compliant Solvent is 100% water-free and alcohol-free and makes clean up a breeze. 


NOTE: Refer to Application Specification for complete installation instructions and Product Data Sheets for appropriate Gaco products and application rates. Refer to for most current information.

Find GacoFlex S20 Series Near You

Ready to renew, not re-roof? Find GacoFlex S20 Series at a store near you. Want more info? Contact a local Gaco area manager with questions and learn more about silicone roof coating prices, the long-term benefits of a silicone-coated roof, and more commercial roofing products for flat and low slope roofs.

S20 Silicone System